A wide variety of modulation techniques exist for wireless communication. For example, many linear modulation techniques exist, such as various quadrature amplitude modulation (QAM) techniques. These include 16 QAM, 64 QAM, and others. Furthermore, many new linear modulation techniques will likely emerge.
Linear modulation is usually well suited to low output power regimes, but often tends to be noisy at high levels of output power. Therefore, at higher power levels, linear modulation may require substantial filtering or other processing to limit signal corruption. This processing can cause undesirable power usage and design complexity at the wireless transmitter.
Polar modulation is one alternative to linear modulation in which the amplitude and phase of the carrier wave are modulated directly. Polar modulation schemes are often viewed as being better suited to high power levels relative to linear modulation schemes. Unfortunately, polar modulation typically performs poorly at low power levels.